1. Field of the Invention
The present invention relates to a power-driven hedge trimmer, more particularly, to a power-driven hedge trimmer with a movable front handle.
2. The Prior Arts
Common hedge trimmers on the market nowadays usually include a power and trimming assembly and a gripping assembly. The power and trimming assembly mainly consists of a motor and a cutting blade. The motor is able to drive the blade to reciprocate in order to achieve hedge trimming with the reciprocating motion of the cutting blade.
Please refer to the hedge trimmer of Taiwan Design Patent No. D112185, which is shown in FIG. 1 of the present invention. As shown in FIG. 1, in order for a user to steadily hold the hedge trimmer 1a during the operation while the hedge trimmer 1a is vibrating, the gripping assembly usually consists of a front gripping portion 1a and a rear gripping portion 13a, so the user may operate the hedge trimmer 1a with both hands. The front gripping portion 11a in the conventional hedge trimmer 1a is attached to a front end of the rear gripping portion 13a. The front griping portion 11a is vertically aligned with the rear gripping portion 13a; in addition, the front gripping portion 11a and the rear gripping portion 13a are attached to a front side and a rear side of the motor 3a respectively.
Generally speaking, the front gripping portion 11a is disposed on a same axis as the blade to serve as a point of support for the gripping of the machine. In some examples of the conventional hedge trimmer 1a, the rear gripping portion 13a can be adjustable; however, the front gripping portion 11a, the motor 3a and the cutting blade 5a are permanently connected with each other.
FIG. 1 illustrates a front-cutting state of the hedge trimmer 1a. During the front-cutting operation, the rear gripping portion 13a is gripped by the right hand of the operator, and the front gripping portion 11a is gripped by the left hand of the operator (when the operator is right-handed). In addition, in order for the operator to hold the hedge trimmer 1a with a comfortable posture, the left hand of the operator is above the hedge trimmer 1a during the operation. When the hedge trimmer 1a is used for side-cutting, it has to be rotated by 90°. Nevertheless, such rotation is performed by using the wrists of the operator as the pivot points of the rotation, and performing the rotation in such a way may cause the left hand of the operator to deviate from the original position to the right (or left) side of the hedge trimmer 1a. Even though the rear gripping portion 13a may be adjusted before or after the rotation of the hedge trimmer 1a, the left hand of the operator is still turned by 90° in both cases. As a result, both hands of the operator are put in different positions with respect to the original gripping positions after the rotation of the hedge trimmer 1a, thus making the operation of the hedge trimmer 1a rather difficult and awkward.
During the actual operation, the hedge trimmer 1a needs to be rotated to switch between the front-cutting state and the side-cutting state frequently. Since the pivot points of the rotation of the hedge trimmer 1a are the wrists of the operator, the wrists of the operator have to be turned and twisted frequently, and the gripping positions of the left and right hand of the operator are also constantly changing in order for the operator to maintain a most effortless posture for gripping the hedge trimmer 1a. 
Notably, when rotating the hedge trimmer 1a, the center of gravity and balance thereof are also constantly changing, and the operator needs to spend extra effort to maintain the center of gravity and the balance of the hedge trimmer 1a. If the operator fails to hold the hedge trimmer 1a properly, not only can the hedge trimmer 1a be damaged from falling and hitting the ground, but also the safety of personnel can be endangered. In addition, since the front gripping portion 11a and the rear gripping portion 13a are connected at two opposite ends of the motor 3a, the operator needs to put in extra force in a horizontal direction to hold the weight of the hedge trimmer 1a and to maintain the center of gravity thereof.
Furthermore, the gripping assembly and the power and trimming assembly of conventional hedge trimmers are connected with each other with only one single rotary shaft. Such structure not only has a low rigidity, but also has a low stability due to the vibration of the motor during the operation of the hedge trimmer.